Figure 2.

Geometric setting when a smaller detector is applied and the center of rotation (C) is offset relative to the source-detector axis which is aligned with the central X-ray. Note, that only the darker grey-shaded inner circular portion of a circular field of view (FOV) remains in the beam over the entire circle (360°). The light grey-shaded portions of the FOV outside that area are only in the beam over a maximum angular range of 180° plus cone angle (depending on the imaging geometry and their distance from the point of rotation). For a point P located on the outer border of the object, this angle is defined by the two source positions (1,2) displayed here